1. Field of the Invention
This application relates to devices for production of truss members. More particularly, it concerns relatively inexpensive devices for precision cutting the ends of lumber to form chords and webs for fabrication of wood trusses.
2. Description of the Prior Art
Consideration of the recent past and probable future of new home construction indicates a continuing desire by would-be home buyers to purchase homes with such outstanding features as volume ceilings of every conceivable design. In contrast to residential building home designs up to a few years ago, with the advent of in house computer designs and engineering, virtually any roof truss design is now limited only to one's imagination. Architects, builders and would-be owners now and for the foreseeable future demand buildings that require roof trusses involving a wide spectrum of chord and web angles, not at all like the identical, "cookie cutter" trusses that were typical of the building designs prior to this new trend in computerized building design and construction. However, the cutting and fabricating end of the roof truss industry is falling behind the trend in this truss design revolution.
Basically, with few exceptions, the truss fabricating manufacturers continue to cut and assemble roof trusses as they have for 20 or more years. In the years from the early 1950's to the early 1980's, flat ceilings with low pitched roofs provided little challenge to design, cutting and fabrication methods. Many truss fabrication shops relied almost entirely on radial arm saws for most of the cutting needs. As a change, a popular introduction was the "component saw", consisting of 4 or more saw blades capable of making multiple angled cuts to each piece of lumber fed in rapid succession thru the machine. Although the set up time in the use of this type saw is slow and requires rechecking, the time spent can be justified when making a good number of identical pieces. However, the component saws are large, needing approximately 14'.times.60' of floor space, and very expensive. Hence, this type machine is designed for high volume, repetitive member design trusses. Other similar type saws came onto the market to fulfil the need for high rate production of "cookie cutter" kind of trusses. In today's market of one-of-a-kind (OOAK) truss designs, requiring few repetitive webs and chords for a given building, the component saws for producing "cookie cutter" trusses are sitting idle much of the time since demand for this type trusses are now becoming a rarity.
In view of the situation discussed above, there exists a need for power-saw devices that can produce OOAK type trusses without need for arduous set-up and recheck routines and, particularly, such devices that are low in cost to purchase and maintain.
There are some saw devices on the market today designed to handle the OOAK trusses. These saws (which are basically a modified radial arm saw mounted to a specially designed cutting table) are fast in set-up time and cutting, but these saws are very expensive.
It is known to use protractors in conjunction with power saws to guide them in the cutting of wood, plastics or the like as disclosed in U.S. Pat. Nos. 2,803,271, 4,320,678, 4,608,898 and 4,945,799, but the devices so disclosed are not capable of effective use in the production of OOAK roof trusses.